The fact they know no-one who uses WhatsApp is a giveaway of their demografy as well. In many countries "not having WhatsApp" equals "not participating in anything". In my country everything, from my insurance help desk to the coordination for a friend's birthday gift happens on WA.
Despite my reluctance to use Meta projects, I read and write far, far more WA messages per day than emails.
Despite my reluctance to use Meta projects, I read and write far, far more WA messages per day than emails.